Methods of forming a degradable component

ABSTRACT

Methods of using a component in a subterranean wellbore include positioning a component including a degradable thermoset polymer material in a wellbore location, obstructing flow with the component, exposing the component to an acidic solution to degrade the selectively degradable thermoset polymer material and to remove the component from the wellbore location, and flowing a fluid through the wellbore location where the component was positioned. Methods of forming a component of a wellbore system include forming at least a portion of the component to comprise a degradable thermoset polymer material. Wellbore systems include at least one component including a selectively degradable thermoset polymer material. The selectively degradable thermoset polymer material may be a polyhexahydrotriazine (“PHT”) material.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.14/526,309, filed Oct. 28, 2014, now U.S. Pat. No. 9,856,411, issuedJan. 2, 2018, the disclosure of which is hereby incorporated herein inits entirety by this reference.

FIELD

Embodiments of the present disclosure relate to wellbore systems thatinclude components to be removed from the wellbore including, but notlimited to, bridge plugs, gas lift valve plugs, hydraulic fracturingballs (“frac balls”), and isolation plugs. Embodiments also relate tomethods of using and forming such components of wellbore systems.

BACKGROUND

Processes of subterranean drilling, completion, and production ofwellbores utilize tools and components to form wellbores and to extractoil and gas from the formation surrounding the wellbores. Some of thewellbore system components may form temporary obstructions that arelater removed for further drilling or completion activities. Bridgeplugs, valve plugs, gravel-pack screens, and drop balls for hydraulicfracturing, expandable reamers and stabilizers, etc., are examples ofwellbore system components that each form temporary obstructions. Knownmethods of removing such components include drilling through thecomponents, extending a wireline into the wellbore for removal orrepositioning of the components, activating a downhole mechanism forremoval or repositioning of the components, reversal of fluid flow, ordegradation, dissolution, or decomposition of the components.

One known decomposable material used in components of wellbore systemsis IN-TALLIC®, available from Baker Hughes Incorporated of Houston, Tex.The IN-TALLIC® material is a controlled electrolytic metallic (“CEM”)nanostructured material generally described in, for example, U.S. patentapplication Ser. No. 12/633,682 to Xu et al. and assigned to BakerHughes Incorporated, titled “NANOMATRIX POWDER METAL COMPACT,” filedDec. 8, 2009 (hereinafter “the '682 application”), the entire disclosureof which is incorporated herein by this reference. The IN-TALLIC®material is slightly reactive with fresh water, will disintegrate at ahigher rate in salt water (brine) than in water, and will disintegrateat a higher rate in a 5% hydrochloric acid solution than in salt water.

A known dissolvable thermoplastic polymer used in components of wellboresystems is poly(glycolic acid) (“PGA”). PGA is water soluble and,therefore, components formed of PGA can be dissolved in water.

BRIEF SUMMARY

Embodiments of the present disclosure include methods of using acomponent in a subterranean wellbore. In accordance with such methods, acomponent is positioned in a wellbore location to obstruct flow of afluid through the wellbore location. The component includes a degradablethermoset polymer. Flow of a fluid through the wellbore location isobstructed with the component, without degrading the degradablethermoset polymer. The component is exposed to an acidic solution todegrade the selectively degradable thermoset polymer and to remove thecomponent from the wellbore location. A fluid is flowed through thewellbore location where the component was positioned.

Additional embodiments of the present disclosure include methods offorming a component of a wellbore system, including forming at least aportion of the component to include a degradable thermoset polymermaterial. To form the at least a portion of the component to include thedegradable thermoset polymer material, paraformaldehyde is combined witha diamine material in a solvent. The combination of paraformaldehyde,diamine material, and solvent is cured at an elevated temperature of atleast about 50° C. to form a polyhexahydrotriazine material.

Further embodiments of the present disclosure include a wellbore systemthat includes at least one component comprising a selectively degradablethermoset polymer material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an embodiment of a wellbore system according to the presentdisclosure.

FIG. 2 illustrates a flowchart of an example process for using at leastone component in a wellbore operation according to an embodiment of thepresent disclosure.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof, and in which is shown,by way of illustration, specific embodiments in which the presentdisclosure may be practiced. These embodiments are described insufficient detail to enable a person of ordinary skill in the art topractice the present disclosure. However, other embodiments may beutilized, and structural, chemical, and process changes may be madewithout departing from the scope of the disclosure. The illustrationspresented herein are not meant to be actual views of any particularsystem, device, structure, or process, but are idealized representationsthat are employed to describe embodiments of the present disclosure. Thedrawings presented herein are not necessarily drawn to scale.

As used herein, the term “substantially” in reference to a givenparameter, property, or condition means and includes to a degree thatone skilled in the art would understand that the given parameter,property, or condition is met with a small degree of variance, such aswithin acceptable manufacturing tolerances. For example, a parameterthat is substantially met may be at least about 90% met, at least about95% met, or even at least about 99% met.

The embodiments of the present disclosure include methods of usingdegradable components in a wellbore, materials for degradable wellborecomponents, and methods of forming degradable wellbore components.Degradable wellbore components of the present disclosure may include aselectively degradable thermoset polymer (e.g., a thermoset polymercapable of selective decomposition, disintegration, and/ordepolymerization). By way of example, the degradable thermoset polymermay be degradable when exposed to an acidic solution of sufficientacidity, such as a solution of hydrochloric acid or sulfuric acid ofless than about 2.0 pH. The degradable thermoset polymer may be apolyhexahydrotriazine (“PHT”) material. The degraded components of theselectively degradable thermoset polymer may be dissolvable in anaqueous or organic solution or solvent (e.g., water), or capable ofbeing suspended in an aqueous or organic solution or solvent, so as toallow them to be carried out from the wellbore by an aqueous or organicsolution or solvent after the thermoset polymer has been selectivelydegraded.

Referring to FIG. 1, a wellbore system 100 includes at least onecomponent 110 within a subterranean wellbore 120 of a formation 130. Theat least one component 110 of the wellbore system 100 may be a componentthat is configured to be temporarily positioned at a predeterminedwellbore location within the wellbore 120 and to be selectively removedfrom the predetermined wellbore location. By way of example and notlimitation, the at least one component 110 may be a bridge plug, a dropball (e.g., a so-called “frac ball” or “isolation ball”), a drop ballseat, an isolation plug, a valve plug (e.g., a plug of a gas lift valve,such as for a replacement of a commercially available TRANSMATIC™ plug),an expandable reamer, a stabilizer, a polymer for retaining steel beads(such as for a replacement of a binder in commercially availableTELEPERF™ systems), a perforation gun body, or a gravel-pack screen. Insome embodiments, the at least one component 110 may be a portion of alarger component or tool 115 (shown in FIG. 1 in dashed lines). Thelarger component or tool 115 of the wellbore system 100 may includeportions or elements other than the at least one component 110, such asa drop ball seat 140 (shown in FIG. 1 in dashed lines), drill bit,sleeve, packer, etc. During use, the at least one component 110 mayprovide a temporary obstruction to fluid flow in the wellbore 120. Theat least one component 110 may provide a temporary obstruction withoutexhibiting degradation while in use as a temporary obstruction.

At least a portion of the at least one component 110 may be formed of aselectively degradable thermoset polymer material that may be degraded(e.g., decomposed, depolymerized, and/or disintegrated) upon exposure toan acidic solution having a sufficiently low pH. For example, thesufficiently low pH may be below a threshold of about 2.0 pH. Thedegradable thermoset polymer material may not degrade upon exposure to afluid, such as water, brine, hydrocarbon fluid, hydraulic fracturingfluid, or drilling mud, having a pH above the threshold. An example ofsuch a selectively degradable thermoset polymer material is apolyhexahydrotriazine (“PHT”) material, such as a PHT material describedin Garcia et al., “Recyclable, Strong Thermosets and Organogels viaParaformaldehyde Condensation with Diamines,” Science Magazine, vol.344, pp. 732-735, May 16, 2014, and its Supplementary Materials, whichis incorporated herein in its entirety by this reference.

In some embodiments, the at least one component 110 may be at leastsubstantially fully formed of the degradable thermoset polymer material.In other embodiments, only a portion, such as an outer portion or one ormore selected regions, of the at least one component 110 may be formedof the degradable thermoset polymer material.

The PHT material used in at least a portion of the at least onecomponent 110 may be formed by combining paraformaldehyde with a diaminematerial (e.g., an aliphatic diamine material) in a solvent and curingthe combination at an elevated temperature. By way of example and notlimitation, the diamine material may be commercially available dianilinematerial, such as 4,4′-oxydianiline, 4,4′-(9-fluorenylidene)dianiline,bis-(3-aminophenyl)-methanone, 4,4′-(1,3-phenylenedioxy)dianiline,4,4′-(4,4′-isopropylidenediphenyl-1,1′-diyldioxy)dianiline, or4,4′-methylenedianiline. For polymerization to occur, the solvent mayinclude N-methylpyrrolidone (“NMP”), such as in a substantiallystoichiometric amount. Since paraformaldehyde and diamine materialsinclude generally polar molecules, the solvent may also include one ormore additional polar solvents to dissolve the paraformaldehyde anddiamine precursor materials, such as one or more of dimethylformamide(“DMF”), acetone, dimethyl sulfoxide (“DMSO”), and acetonitrile, forexample. The diamine material and paraformaldehyde may be combined in amolar ratio of, for example, between about 1:2 and about 1:10,respectively, such as about 1:2.5. The paraformaldehyde, diaminematerial, and solvent may be stirred together to dissolve theparaformaldehyde and diamine material in the solvent, such as at about50° C. for at least about fifteen minutes.

The combination of the diamine material and paraformaldehyde in asolvent may then be cured at an elevated temperature, such as, forexample, by heating at about 50° C. for one hour, ramping thetemperature of the combination from about 50° C. to about 200° C. over aperiod of about one hour, and then holding the combination at about 200°C. for about one hour. Relatively large volumes of the combination maycure by holding the combination at the same temperatures for longerperiods of time. In some embodiments, the combination may be cured byheating or holding the combination at the elevated temperature in alow-pressure environment, such as a vacuum. Such modifications of theexample curing scheme listed above may be determined by one of ordinaryskill in the art given a sample size, a particular composition, etc. Inany case, the process or a variation thereof may be performed to resultin a cured thermoset polymer PHT material.

The PHT material may be cured in a mold (e.g., in an injection moldingmachine or a cast) having a predetermined shape to form the at least onecomponent 110, and/or a volume of the PHT material may be formed andlater shaped (e.g., cut, machined) to form the at least one component110.

The PHT material may be degradable in a sufficiently acidic solution.For example, the PHT material may degrade (e.g., depolymerize) whenexposed to an acidic solution having a pH of less than about 2.0. On theother hand, the PHT material may be chemically stable when exposed to afluid having a pH of more than about 2.0, such as about 3.0 or more.Accordingly, the PHT material may be mechanically and chemically stablein many wellbore fluids, such as water, salt water (i.e., brine),hydrocarbon fluids, drilling mud, hydraulic fracturing fluids, etc.However, the PHT material may be selectively degradable by exposing thePHT material to a sufficiently acidic solution (having, e.g., a pH ofabout 2.0 or less).

In some embodiments, prior to curing, one or more filler materials maybe added to the combination of paraformaldehyde and diamine material inthe solvent. Such filler materials may be included to modify themechanical properties of the resulting PHT material. By way of exampleand not limitation, filler materials may include one or more of thefollowing: carbon nanotubes (e.g., in quantities of between about 2% and5% by weight of the total combination), graphene, graphene oxide,graphite, carbon fibers, glass fibers, nylon particles, controlledelectrolytic metallic (“CEM”) particles, molybdenum sulfide,water-soluble poly(vinyl alcohol) fibers, or active metal particles orfibers (e.g., aluminum, magnesium, zinc, manganese).

In some embodiments, the filler material may comprise a material thatdissolves or degrades in water or an acidic solution, such that thereactive filler material may dissolve or degrade upon exposure to theacidic solution used to degrade the PHT material. In some embodiments,the filler material may comprise a reactive material having acomposition that will react with the acidic solution used to degrade thePHT material. For example, CEM or other metal particles or fibers mayalso degrade in the presence of the acidic solution used to degrade thePHT material. Additionally, reinforcing fibers of water-solublepolymers, such as poly(vinyl alcohol), can completely dissolve in theacidic media used to degrade the PHT material. In other embodiments, thefiller material may be a non-reactive or less reactive material that isnot dissolvable or degradable (or that is dissolvable or degradable at asubstantially slower rate than the PHT material) in the acidic solutionused to degrade the PHT material. Such non-reactive or less reactivefiller materials may be sized sufficiently small to be flushed away influids within the wellbore 120 upon degradation of the PHT material, toenable removal of the at least one component 110 via degradation of thePHT material, even in a case where the filler materials are notsimilarly degradable or dissolvable. For example, carbon nanotubes,carbon fibers, and glass fibers may be used in sufficiently smallquantities and/or small fiber or particle sizes to be flushed away inwellbore fluids upon degradation of the PHT material in the acidicsolution.

In further embodiments, the at least one component 110 may comprise afiber matrix composite material that includes the PHT material as thematrix phase, and fibers as a discontinuous reinforcing phase. Forexample, the combination of paraformaldehyde, diamine material, andsolvent may be applied to a glass, KEVLAR®, carbon fiber, or other fiberfabric or weave and cured at ambient pressure or reduced pressure toform the at least one component 110 or a portion thereof.

By way of example and not limitation, the PHT material may havemechanical properties sufficient to withstand conditions within thewellbore 120 during use of the at least one component 110 including thePHT material. By way of example and not limitation, the PHT materialused for the at least a portion of the at least one component 110 may bemechanically stable to at least about 50° C., to at least about 100° C.,to at least about 200° C., or even to at least about 220° C., dependingon a selected method of manufacture (e.g., depending on selectedchemical component(s) and ratios, selected filler material(s), curingtemperature, curing time, etc.). The PHT material may have a Young'smodulus of at least about 10.0 GPa (e.g., about 14.0 GPa, or even about20.0 GPa when carbon nanotube fillers are included in the PHT material).The at least one component 110 including the PHT material may havesufficient strength to remain mechanically stable during use in thewellbore 120 when exposed to wellbore fluid pressure of at least about3,000 psi, at least about 5,000 psi, at least about 8,000 psi, or atleast about 10,000 psi, depending on the application and depending onthe particular composition and manufacturing process used to form thePHT material.

The PHT material may have improved mechanical properties compared toknown degradable thermoplastic polymers, such as PGA. For example, thePHT material may have a higher compressive strength, stability up to ahigher temperature, and greater (e.g., complete) resistance todissolution in water, compared to PGA. Compared to IN-TALLIC® materials,the PHT material may have a greater (e.g., complete) resistance todissolution in water or salt water, and, therefore, may be used inapplications with water or salt water without degradation or with onlylow levels of degradation. In addition, the PHT material may be easierand/or cheaper to manufacture than IN-TALLIC® materials of a similarsize and shape.

FIG. 2 illustrates a flowchart of an example process 200 for using atleast one component 110 (FIG. 1) in a wellbore operation, such as adrilling, completion, or production operation. As indicated at operation202 of FIG. 2, and also referring to elements shown in FIG. 1, the atleast one component 110, which includes a degradable thermoset polymer,may be positioned in a wellbore location. The wellbore location may be afixed location relative to the wellbore 120 or relative to a tool withinthe wellbore 120. The at least one component 110 may temporarilyobstruct fluid flow in the wellbore location, such as flow of drillingmud, water, brine, completion fluid, hydraulic fracturing fluid,hydrocarbon fluid, a slurry, etc. Depending on the identity and functionof the at least one component 110, the obstruction of the fluid flow mayfully prevent fluid flow past the wellbore location (such as inembodiments that the at least one component 110 is a bridge plug, anisolation plug, or a drop ball for an isolation plug), or may simplydivert fluid flow around and past the at least one component 110 orportions thereof (such as in embodiments that the at least one component110 is a hydraulic fracturing ball, a valve plug, or a gravel-packscreen).

Optionally, in some embodiments, the at least one component 110 may beexposed to an elevated temperature and/or pressure, as indicated atoperation 204 of FIG. 2. For example, elevated temperatures to which theat least one component 110 may be exposed in the wellbore 120 may be atleast about 50° C., at least about 100° C., at least about 150° C., orat least about 200° C. By way of further example, elevated pressures towhich the at least one component 110 may be exposed in the wellbore 120may be at least about 3,000 psi, at least about 5,000 psi, at leastabout 8,000 psi, or at least about 10,000 psi. The at least onecomponent 110, including the degradable thermoset polymer thereof, maybe configured to be mechanically stable at such temperatures and/orpressures. For example, the degradable thermoset polymer of the at leastone component 110 may be formed of materials and by processes (describedabove) to enable the degradable thermoset polymer to undergo glasstransition (and resulting mechanical softening) at or above the elevatedtemperature and/or elevated pressure to which the at least one component110 is to be exposed in a particular application.

After the at least one component 110 (FIG. 1) has served its purpose inthe wellbore location, the at least one component 110 may be exposed toan acidic solution (e.g., a solution of hydrochloric acid or sulfuricacid) to degrade the degradable thermoset polymer thereof, as indicatedat operation 206 of FIG. 2. Depending on several factors, such as theacidity, temperature, and pressure of the acidic solution, and the size,shape, properties, and composition of the at least one component 110,the degradation of the degradable thermoset polymer sufficient to removethe at least one component 110 from the wellbore location may becompleted within several minutes (e.g., about 10 minutes) up to severalhours (e.g., about 6 hours) of exposure to the acidic solution.Accordingly, in some embodiments, efficient removal of the at least onecomponent 110 from the wellbore location in which the at least onecomponent 110 is positioned may be accomplished without conventionalintervention techniques, such as wireline intervention, flow reversal,drilling, etc.

As indicated at operation 208 of FIG. 2, after the at least onecomponent 110 has served its purpose and is removed from the wellborelocation through acid degradation of the degradable thermoset polymerthereof, a fluid may be flowed through the wellbore location where theat least one component 110 (FIG. 1) was previously positioned. Forexample, in a drilling operation, drilling mud may be flowed through thewellbore location to resume drilling. By way of another example, in acompletion operation, hydraulic fracturing fluids, water, or a gravelslurry may be flowed through the wellbore location. By way of a furtherexample, in a production operation, hydrocarbon fluids or gas for a gaslift operation may be flowed through the wellbore location after the atleast one component 110 is removed by acid degradation.

By way of one example, referring to FIG. 1 and FIG. 2, the at least onecomponent 110 may be a drop ball, at least a portion of which is adegradable thermoset polymer material (e.g., a PHT material). The dropball may be sized to fit through other tools and components of thewellbore system 100 (e.g., drill pipe, casing, joints) until coming torest against the drop ball seat 140 of the wellbore system 100. Inoperation, the drop ball may be positioned within the wellbore 120 bydropping the drop ball into a fluid flow within the wellbore 120 to forma seal against the drop ball seat 140. Fluid pressure may be appliedagainst the seated drop ball, which forms a temporary flow obstructionin the wellbore 120, to apply a force to the drop ball seat 140. Theforce may actuate a mechanism, such as a fracturing valve to open portsin the wellbore to facilitate fracturing or application of chemicaltreatments to the formation 130. After the drop ball has served itspurpose in the wellbore location, the temporary obstruction formed bythe drop ball may be removed via acid degradation of the drop ball or aportion thereof. When the drop ball is sufficiently degraded, aremaining portion of the drop ball may be sufficiently small to dropthrough an opening in the drop ball seat 140, and the temporaryobstruction formed by the drop ball is removed from the wellborelocation at the drop ball seat 140. In some embodiments, furtherdegradation of the drop ball may occur upon further exposure to anacidic solution, such that up to the entire drop ball may be fullydegraded to avoid creating an unwanted obstruction elsewhere in thewellbore 120.

Additional non-limiting example embodiments of the present disclosureare set forth below.

Embodiment 1: A method of using a component in a subterranean wellbore,the method comprising: positioning a component comprising a degradablethermoset polymer in a wellbore location; obstructing, with thecomponent, flow of a fluid through the wellbore location withoutdegrading the thermoset polymer; exposing the component to an acidicsolution to degrade the degradable thermoset polymer and to remove thecomponent from the wellbore location; and flowing a fluid through thewellbore location where the component was positioned.

Embodiment 2: The method of Embodiment 1, wherein positioning acomponent in a wellbore location comprises positioning a drop ballagainst a drop ball seat.

Embodiment 3: The method of Embodiment 1 or Embodiment 2, whereinpositioning a component comprising a degradable thermoset polymer in awellbore location comprises positioning the component comprising apolyhexahydrotriazine material in the wellbore location.

Embodiment 4: The method of any one of Embodiments 1 through 3, whereinexposing the component to an acidic solution comprises exposing thecomponent to the acidic solution exhibiting a pH of less than about 2.0.

Embodiment 5: The method of any one of Embodiments 1 through 4, whereinflowing a fluid through the wellbore location comprises flowing a fluidselected from the group consisting of water, salt water, a hydrocarbonfluid, a hydraulic fracturing fluid, drilling mud, a gravel slurry,completion fluid, and gas for a gas lift operation.

Embodiment 6: The method of any one of Embodiments 1 through 5, furthercomprising, prior to exposing the component to an acidic solution,exposing the component in the wellbore location to at least one of anelevated temperature of at least about 50° C. and an elevated pressureof at least about 3,000 psi.

Embodiment 7: The method of Embodiment 6, further comprising exposingthe component in the wellbore location to at least one of an elevatedtemperature of at least about 100° C. and an elevated pressure of atleast about 5,000 psi.

Embodiment 8: A method of forming a component of a wellbore system, themethod comprising: forming at least a portion of the component tocomprise a degradable thermoset polymer material, comprising: combiningparaformaldehyde with a diamine material in a solvent; and curing thecombination of the paraformaldehyde, diamine material, and solvent at anelevated temperature of at least about 50° C. to form apolyhexahydrotriazine material.

Embodiment 9: The method of Embodiment 8, wherein combiningparaformaldehyde with a diamine material in a solvent comprisescombining the paraformaldehyde with the diamine material in a solventcomprising N-methylpyrrolidone.

Embodiment 10: The method of Embodiment 8 or Embodiment 9, whereinforming at least a portion of the component comprises forming the atleast a portion of the component within a mold.

Embodiment 11: The method of any one of Embodiments 8 through 10,wherein forming at least a portion of the component further comprisesadding at least one filler material to the combination of theparaformaldehyde, diamine material, and solvent, the at least one fillermaterial selected from the group consisting of graphene, graphene oxide,graphite, carbon nanotubes, carbon fibers, nylon particles, controlledelectrolytic metallic particles, molybdenum sulfide, water-solublepoly(vinyl alcohol) fibers, and active metal particles or fibers.

Embodiment 12: The method of any one of Embodiments 8 through 11,wherein forming at least a portion of the component to comprise adegradable thermoset polymer material comprises substantially fullyforming the component of the degradable thermoset polymer material.

Embodiment 13: A wellbore system, comprising: at least one componentcomprising a selectively degradable thermoset polymer material.

Embodiment 14: The wellbore system of Embodiment 13, wherein theselectively degradable thermoset polymer material comprises apolyhexahydrotriazine material.

Embodiment 15: The wellbore system of Embodiment 13 or Embodiment 14,wherein the polyhexahydrotriazine material is formed of materialscomprising a diamine material selected from the group consisting of4,4′-oxydianiline, 4,4′-(9-fluorenylidene)dianiline,bis-(3-aminophenyl)-methanone, 4,4′-(1,3-phenylenedioxy)dianiline,4,4′-(4,4′-isopropylidenediphenyl-1,1′-diyldioxy)dianiline, and4,4′-methylenedianiline.

Embodiment 16: The wellbore system of any one of Embodiments 13 through15, wherein the at least one component is selected from the groupconsisting of a drop ball, a drop ball seat, an isolation plug, a valveplug, an expandable reamer, a stabilizer, a perforation gun body and agravel-pack screen.

Embodiment 17: The wellbore system of any one of Embodiments 13 through16, wherein the at least one component consists essentially of theselectively degradable thermoset polymer material.

Embodiment 18: The wellbore system of any one of Embodiments 13 through17, wherein the selectively degradable thermoset polymer materialcomprises at least one filler material.

Embodiment 19: The wellbore system of Embodiment 18, wherein the atleast one filler material is selected from the group consisting ofgraphene, graphene oxide, graphite, carbon nanotubes, carbon fibers,glass fibers, nylon particles, controlled electrolytic metallicparticles, molybdenum sulfide, water-soluble poly(vinyl alcohol) fibers,and active metal particles or fibers.

Embodiment 20: The wellbore system of any one of Embodiments 13 through19, wherein the selectively degradable thermoset polymer material isselectively degradable by exposure to an acidic solution having a pH ofless than about 2.0.

The embodiments of the disclosure described above and illustrated in theaccompanying drawing figures do not limit the scope of the invention,since these embodiments are merely examples of embodiments of thedisclosure. The invention is encompassed by the appended claims andtheir legal equivalents. Any equivalent embodiments lie within the scopeof this disclosure. Indeed, various modifications of the presentdisclosure, in addition to those shown and described herein, such asother combinations and modifications of the elements described, willbecome apparent to those of ordinary skill in the art from thedescription. Such embodiments, combinations, and modifications also fallwithin the scope of the appended claims and their legal equivalents.

What is claimed is:
 1. A method of forming a component of a wellboresystem, the method comprising: forming at least a portion of thecomponent of the wellbore system to comprise a degradable thermosetpolymer material, comprising: combining paraformaldehyde with a diaminematerial in a solvent; and curing the combination of theparaformaldehyde, diamine material, and solvent at an elevatedtemperature of at least about 50° C. to form a polyhexahydrotriazinematerial, the polyhexahydrotriazine material being mechanically stablewhen exposed to wellbore temperatures in a range between 50° C. and 220°C., inclusive, and at wellbore fluid pressures equal to or greater thanabout 3,000 psi.
 2. The method of claim 1, wherein combiningparaformaldehyde with a diamine material in a solvent comprisescombining the paraformaldehyde with the diamine material in a solventcomprising N-methylpyrrolidone.
 3. The method of claim 1, whereinforming at least a portion of the component comprises forming the atleast a portion of the component within a mold.
 4. The method of claim1, wherein forming at least a portion of the component further comprisesadding at least one filler material to the combination of theparaformaldehyde, diamine material, and solvent, the at least one fillermaterial selected from the group consisting of graphene, graphene oxide,graphite, carbon nanotubes, carbon fibers, nylon particles, controlledelectrolytic metallic particles, molybdenum sulfide, water-solublepoly(vinyl alcohol) fibers, and active metal particles or fibers.
 5. Themethod of claim 1, wherein forming at least a portion of the componentof the wellbore system to comprise a degradable thermoset polymermaterial comprises substantially fully forming the component of thedegradable thermoset polymer material.
 6. The method of claim 1, whereincombining paraformaldehyde with a diamine material in a solventcomprises combining the paraformaldehyde with the diamine material in asolvent comprising at least one of dimethylformamide, acetone, dimethylsulfoxide, and acetonitrile.
 7. The method of claim 1, wherein combiningparaformaldehyde with a diamine material in a solvent comprisescombining the paraformaldehyde with the diamine material selected fromthe group consisting of 4,4′-oxydianiline,4,4′-(9-fluorenylidene)dianiline, bis-(3-aminophenyl)-methanone,4,4′-(1,3-phenylenedioxy)dianiline,4,4′-(4,4′-isopropylidenediphenyl-1,1′-diyldioxy)dianiline, and4,4′-methylenedianiline in the solvent.
 8. The method of claim 1,wherein combining paraformaldehyde with a diamine material in a solventcomprises dissolving the paraformaldehyde and the diamine material inthe solvent.
 9. The method of claim 1, wherein combiningparaformaldehyde with a diamine material in a solvent comprisescombining paraformaldehyde with the diamine material in a molar ratio ofbetween about 1:2 and about 1:10.
 10. The method of claim 1, whereinforming at least a portion of the component of the wellbore system tocomprise a degradable thermoset polymer material comprises forming adrop ball of the wellbore system to comprise the degradable thermosetpolymer material.
 11. The method of claim 1, wherein forming at least aportion of the component of the wellbore system to comprise a degradablethermoset polymer material comprises forming at least a portion of atleast one component selected from the group consisting of a drop ball, adrop ball seat, an isolation plug, a valve plug, an expandable reamer, astabilizer, a perforation gun body, and a gravel-pack screen to comprisethe degradable thermoset polymer material.
 12. The method of claim 1,wherein the degradable thermoset polymer material is selectivelydegradable by exposure to an acidic solution having a pH of less thanabout 2.0.
 13. The method of claim 1, wherein curing the combination ofthe paraformaldehyde, diamine material, and solvent at an elevatedtemperature of at least about 50° C. to form a polyhexahydrotriazinematerial comprises heating the combination of the paraformaldehyde,diamine material, and solvent at a temperature of about 50° C. for aboutone hour, increasing the temperature of the combination of theparaformaldehyde, diamine material, and solvent from a temperature ofabout 50° C. to about 200° C. for about one hour, and then holding thetemperature of the combination of the paraformaldehyde, diaminematerial, and solvent at about 200° C. for about one hour.
 14. A methodof forming a component of a wellbore system, the method comprising:forming at least a portion of the component of the wellbore system tocomprise a selectively degradable thermoset polymer material, theselectively degradable thermoset polymer material comprisingpolyhexahydrotriazine material, the polyhexahydrotriazine material beingmechanically stable when exposed to wellbore temperatures in a rangebetween 50° C. and 220° C., inclusive, and at wellbore fluid pressuresequal to or greater than about 3,000 psi.
 15. The method of claim 14,wherein forming at least a portion of the component further comprisesadding at least one filler material to the combination of theparaformaldehyde, diamine material, and solvent, the at least one fillermaterial selected from the group consisting of graphene, graphene oxide,graphite, carbon nanotubes, carbon fibers, nylon particles, controlledelectrolytic metallic particles, molybdenum sulfide, water-solublepoly(vinyl alcohol) fibers, and active metal particles or fibers. 16.The method of claim 14, wherein forming at least a portion of thecomponent of the wellbore system to comprise a selectively degradablethermoset polymer material comprises: combining paraformaldehyde with adiamine material in a solvent; and curing the combination of theparaformaldehyde, diamine material, and solvent at an elevatedtemperature of at least about 50° C. to form the polyhexahydrotriazinematerial.
 17. The method of claim 14, wherein forming at least a portionof the component of the wellbore system to comprise a degradablethermoset polymer material comprises forming at least a portion of atleast one component selected from the group consisting of a drop ball, adrop ball seat, an isolation plug, a valve plug, an expandable reamer, astabilizer, a perforation gun body, and a gravel-pack screen to comprisethe degradable thermoset polymer material.
 18. The method of claim 14,wherein forming at least a portion of the component of the wellboresystem to comprise a degradable thermoset polymer material comprisessubstantially fully forming the component of the wellbore system tocomprise the degradable thermoset polymer material.
 19. The method ofclaim 14, wherein the selectively degradable thermoset polymer materialis selectively degradable by exposure to an acidic solution having a pHof less than about 2.0.
 20. The method of claim 14, wherein forming atleast a portion of the component of the wellbore system to comprise aselectively degradable thermoset polymer material comprisessubstantially fully forming the component of the selectively degradablethermoset polymer material.